We recently acquired an fNIR system (fNIR 100) from Biopac and would like to use our Cedrus stimtracker to mark events (we have used the stimtracker with the Biopac MP35 system for some time). We are running Superlab and the stimtracker on a separate machine (mac), and the fNIR on a PC. The only way to bring in the markers is via USB, but we are having some trouble reading the markers. We can find the COM ports, but not get any data from them in any configuration (port 1, port 2, the biopac adapter board, etc). fNIR Systems recommended a straight DB25 to USB cable, but I am unsure of what output to use. Do you have any recommendations as to the output type, cabling or adapter/chipset to use?

I got it to work... odd trick too. We are using a Star Tech DB25 to DB9 Crossed Null modem cable http://www.amazon.com/gp/product/B00066HL50 out of the top DB25 port on the Stim Tracker (without the Biopac Adapter Board). We are communicating with the host computer via a virtual port using this adapter http://www.digikey.com/product-detai...014-ND/1836392. I posted the links, not as a sales promotion, but to specify what we are using, as there may be others who are struggling with the same, or who could check out this solution in other systems.

The trick was that we were using Superlab to trigger the Stim Tracker via a marker delivered on a particular event. We could see the marker indicator on the Stim Tracker but were getting nothing on the COBI screen even though the port was active and COBI was listening on the right com port. When we tried it with a photodiode it lit up in COBI. We can get accurate and reliable marking easily. I am not sure why the marker from Superlab is not working, but we can drive it with the photodiode and get automatic markers.

Has anyone else had trouble with markers from the Superlab being read in other software like this? Could it be a voltage issue? To be honest, I haven't played around much with the event marking in Superlab itself, but it is convenient being able to label events directly.

When sending event markers from SuperLab to StimTracker, seeing the corresponding blue LED light up on StimTrackerís front panel means that the signal has been delivered and is going out on the back.

When doing this test, do you have all eight lines / checkboxes turned on? When troubleshooting connections like this, it is important that all lines be turned on, just to make sure that *something* is being delivered. Afterwards, you can narrow down the number of lines.

If you are turning all eight lines on and still not seeing a signal, then the issue would be the connection between StimTrackerís parallel port output and the receiving computer. If I understood your post correctly, you have something like this:

I tried the test function with all 8 channels selected and again saw the light on the stim tracker indicating that the signal was being received, but nothing on our COBI screen. However, the diode still signals both stim tracker and COBI software appropriately.

We do have the parallel board adapter for use with the Biopac equipment, but have been unable to find a parallel to USB converter that maintains the DB25 connections. Everything that we have seen online is parallel to serial to USB. Some of these do have parallel port emulation abilities however. Would something like that work here, or would we need parallel direct to USB? If the latter, do you have any recommendations about where to find such a converter?

A converter that emulates a parallel port should work, I think. I’m not sure about the different adapters out there. Most of them seem built to connect to a printer. In other words, they are built for output from the computer, whereas what you need is input to the computer.

I suggest that you call B&B Electronics. They are not the cheapest, but they specialize in connecting devices.

A converter that emulates a parallel port should work, I think. I’m not sure about the different adapters out there. Most of them seem built to connect to a printer. In other words, they are built for output from the computer, whereas what you need is input to the computer.

I suggest that you call B&B Electronics. They are not the cheapest, but they specialize in connecting devices.

We are trying to use SuperLab and StimTracker. They are connected through a USB cable (COM4). However, it seems that the SuperLab could not detect a 'StimTracker device'. I wonder why was that.

BTW, using Presentation software, we were able to send out signals to StimTracker using the same COM4 port. But we could not read information from the StimTracker.

You didnít mention which StimTracker model you have. If itís the original StimTracker 1G model, it cannot send event marker information via USB; it can do so only via TTL output.

The newer StimTracker Duo and Quad models do have that ability in hardware, but itís turned off by default to maintain compatibility with application software. We are currently wrapping up work on a (free) firmware update and a new version of Xidon 2 that will allow you to turn this option on, and do a lot more, e.g. signal filtering.